Measuring masses of intact microorganisms holds much interest for the scientific community. Biomass measurements, for example, are useful for determining growth rates and cell yields of the microorganisms of interest.
The conventional ways of quantifying biomass involve both flow cytometry and gravimetric determination. While these methods can be sufficiently accurate, they are laborious and time-consuming. Recently, new technologies, such as quartz crystal microbalances, superconducting quantum interference devices and micromechanical oscillators, have been developed to detect and weigh a single microorganism. However, the errors involved in biomass measurements using these techniques are relatively large (typically more than 10%).
Although mass spectrometry techniques may be useful for determining the mass of relatively small particles, mass spectrometry techniques have been considered ill-suited for mass determination of large biological organisms (e.g., biological organisms having masses in excess of 1×109 Daltons). In part, this is because biological organisms are massive enough to make it difficult to accelerate them to the velocity required for detection using known mass spectrometry techniques.